Was battling amphidinium dinos for a while and these guys popped up. It forms on the sandbed in small thick mats that you can almost peel off the sand. I don’t think they are amphidinium because they are way smaller. This is at the third highest setting on my microscope. The one before I have to use immersion oil. Tested water and N03 was at 0.5 And p04 was at 0.10. Any help or ideas?